1. Field of the Invention
The present invention relates to a permanent resist, and to a permanent resist-laminated substrate and a process for producing a permanent resist-laminated substrate.
2. Related Background Art
Permanent resists are formed on printed wiring boards by a process whereby an active light ray is irradiated in a pattern on a photosensitive resin composition layer formed on a substrate, development is carried out with a developing solution dissolving an alkali metal salt (sodium carbonate, potassium carbonate, etc.), and the substrate is rinsed with purified water or the like. The process usually employs ultraviolet irradiation with a high-pressure mercury lamp, or heating, in order to improve the flexibility, soldering heat resistance, chemical resistance and the like.
In the aforementioned developing method, however, inadequate processing by water rinsing (due to insufficient temperature or time) causes the physically unstable monovalent metal cations (Na+, K+, etc.) from the developing solution to remain on the surface of the permanent resist, leading to such problems as a reduced moisture-resistant insulating property for humid conduction, or electrical signal malfunctions.